1. Field of the Invention
The invention relates to prefabricated building panels which can be rapidly assembled to form structural walls for buildings of various types. Specifically, the invention relates to building panels which incorporate panels of insulating foam.
2. Related Art
Prefabricated building panels incorporating panels of foam insulation are known for providing rapid assembly of building walls having good insulating properties. Prefabricated building panels of this type typically utilize a frame of structural steel for surrounding the foam panel and imparting rigidity and strength thereto. U.S. Pat. No. 4,223,500 to Clark et al. discloses one such panel. The prefabricated building panel disclosed by Clark et al. utilizes a four-sided steel frame which forms a mold that is filled with liquid foam insulation. After the liquid foam insulation has set up in the frame, the panel can be assembled together with other panels to form a complete modular wall.
However, certain drawbacks are associated with the prior art panels which use insulating foam. For example, strength-to-weight ratios have been generally low. Panels which use polymer foams, such as polystyrene, require extensive reinforcement if such panels are to be used to form structural walls. If such reinforcement is made integral with the panel, such as by the addition of a heavy steel frame around the foam sheet, the panels become difficult to transport due to their heavy weight.
Further, insulating panels of the prior art have frequently required additional external reinforcement when used in applications that require walls to withstand high levels of stress. Such applications include, e.g., multi-story structures and structures built in areas prone to earthquakes. In such applications, the use of heavy steel I-beam studs is often necessary to impart the requisite amount of rigidity to walls constructed from insulative foam panels. However, the use of such external reinforcement is costly in that it adds additional steps and materials to the construction process.